Searchable, peer-reviewed, open-access proceedings from bioscience and biomedical conferences

bp0009rdr19 | Male Function and Spermatogenesis | REDR1986

Use of chimaeras to study development

Anderson G. B.

Abstract unavailable© 1987 Journals of Reproduction & Fertility Ltd...

bp0019cpr2 | Gametes and Embryos | CPR2013

Mechanisms affecting litter sex ratio and embryo quality

Oliver G. , Vendramini P.

Sex ratios that deviate from 1:1 have been observed in response to a number of stimuli. In this review we will discuss sex ratio biasing, and the evolutionary and molecular mechanisms thought to underlie this phenomena in mammals. The role of embryo quality will be discussed in relation to sex ratio modulation and epigenetic programing of the embryo. Sex ratio skewing has been studied in many species and several factors have been proposed as influencing secondary sex rat...

bp0004rdr16 | The Corpus Luteum | REDR1998

Luteal peptides and their genes as important markers of ovarian differentiation

Ivell R , Bathgate R , Walther N

Secreted peptide hormones and components of the steroidogenic machinery are molecules that are expressed usually in high amounts and in a time- and cell-specific fashion within the cells that give rise to the bovine corpus luteum. They thus serve as useful markers for the events occurring within the nuclei of these cells that result in differentiation and the expression of the specific luteal phenotype. We have studied the bovine genes of three such luteal products: oxytocin, ...

bp0005rdr19 | Ovary-Uterus-Embryo Interactions | REDR2002

Regulation of embryo survival in cattle

Thatcher WW , Guzeloglu A , Meikle A , Kamimura S , Bilby T , Kowalski AA , Badinga L , Pershing R , Bartolome J , Santos JEP

Evidence is presented that bovine somatotrophin (bST) treatment of lactating dairy cows enhances both expression of oviductal insulin-like growth factor II (IGF-II) mRNA and endometrial insulin-like growth factor binding protein 3 (IGFBP-3) mRNA between day 3 and day 7 of the oestrous cycle. mRNA encoding growth hormone (GH) receptor in endometrial tissues increased between day 3 and day 7 of the oestrous cycle. The changes induced by bST treatment may contribute to stimulatio...

bp0001redr5 | (1) | REDR1980

Endocrine control of spermatogenesis in the ram

Courot M , Ortavant R

Summary. In the ram, the size of the testes is related to the concentrations of FSH, LH and testosterone in the blood. A significant linear relationship is observed between testicular size and the level of FSH until a maximum after which no further increase in testis size is observed. Testicular size is also linearly related to the mean level (25 consecutive hours of sampling) of LH and testosterone in the blood, with apparently no upper limit, and to the freq...

bp0005rdr35 | Ruminant Models for Human Clinical Medicine | REDR2002

Reprogramming the genome: role of the cell cycle

Campbell KHS , Alberio R

In nuclear transfer reconstructed embryos, the co-ordination of donor nuclear and recipient cytoplasmic cell cycle phases is essential to maintain ploidy and prevent DNA damage. However, the stage of the cell cycle at the time of reconstruction and the method of reconstruction may also have a significant impact on the subsequent development of the embryo and fetus through a number of other mechanisms. This paper reviews some of the information currently available and proposes ...

bp0006rdr9 | Gametes and Fertilisation | REDR2006

Development of the dominant follicle: mechanisms of selection and maintenance of oocyte quality

Webb R , Campbell BK

For a follicle to reach dominance, in mono-ovulatory species such as cattle, requires the integration of a number of processes involving both extra-ovarian signals and intra-follicular paracrine and autocrine regulators. Ovarian transplant studies in both cattle and sheep demonstrated that it takes approximately 4 months for primordial follicles to reach dominance. Gonadotrophins are not a prerequisite for the continued growth of pre-antral follicles, unlike antral folliclcs, ...

bp0009rdr10 | (1) | REDR1986

Function of the epididymis in bulls and rams

Amann R. P.

Abstract unavailable© 1987 Journals of Reproduction & Fertility Ltd...

bp0012cpr14 | Nutrition and Environmental Factors Affecting Prolificacy | CPR1985

Influence of light and photoperiodicity on pig prolificacy

R. Claus and U. Weiler ,

Summary. In the wild pig mating activity is seasonal. The main breeding period is in late autumn but a second period may occur around April. It is known from other species that seasonal variations in breeding activity are mainly regulated by photoperiod.In the domestic pig seasonal influences on prolificacy still exist: for example, Al boars not only show decreased steroid synthesis, sperm counts and libido in summer compared with t...